Detinning and degalvanizing scrap.



UNITED STATES PATENT GFFICE.

ALEXANDER s. nausea, or NEWARK, NEW JERSEY, ASSIGNOR T JOHN ii. MAUGHAM,

TRUSTEE FOR A. S. RAMAGE, EVEBLEY M. DAVIS, AND THE FIRM'OF MAUGHAM' a es.

Rom-swing.

Specification of Letters Patent. Application filed July 3, 1909. Serial No. 505,933.

:onrmmive AND DEGALVANIZING sonar:

Patented Feb. '14, 1911.

- To all whom it may concern:

I follows:-I take leadashes or litharge and dissolve them in boiling caustic soda storm Be itknown that I, ALEXANDER S. Ramon,

a citizen of the United States, residingat Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Methods of Detinning and Degalvanizing Scrap, of which ing plumbate of soda. It is necessary to keep an excess of caustic soda present, otherwise from concentrated solutions litharge crystallizes out in the-cold. If sulfate of lead is used, then it may be treated by the method described in Letters Patent No.

950,677, patented March 1, 1910, and so formed into plumbate of soda. The liquor is filtered and run into iron tanks and heated nearly to boiling. Iron cages containing-tin scrap are immersed in the liquor and immediately double decomposition ensues, the lead bein thrown out as spon' metallic lead and-the tin going into solution as stannate of soda. It is preferable to have at least three .tanks containing the; plumbate liquor so that the clean tin scrap is first immersed in the nearly exhausted liquor and then into the stronger liquor so insuring-that all the lead is removed from the weak liquor and that all the tin is removed. from the partially stripped scrap by means of the strongest plumbate liquor. The detinned scrap is then washed and baled. The stannate of soda liquor containing the spongy lead sus pended but no lead in solution is then run through a centrifugal machine and the spongy lead separated and washed. It is ings are run into a series of iron tanks similar to the previous ones and treated with vzinchor galvanized iron scrap in thesame 'way that the plumbate of soda was treated with tin scrap. -We have now zincate of soda in'solution with spongy tin suspended. This latter is so arated and washed in a centrifugal machlne and used to make tin 'saltssuch as tin crystals, or oxychlorid "in the usual way. Thezincate of soda is decomposed in electrolytic cells using. iron anodes and thin zinc sheets as cathodes, by

f1 current of about 20 amperes per squareoot. caustic soda 'isJiberated at the anodes. I "do not aim'to remove all the zinc but only a portion, and the zincateof soda with a large Zinc is deposited on the cathodes and excess of caustic soda is again used in the process to dissolve more lead oxid/j The presence of excess of zincate of soda in the process does not militate against the results.

' Thedezinced ron scrap is washed and sold in that state without bailing, as it is much heavier than the detinned iron scrap.

The reactions all take place at about 180 Fahrenheit. i

I claim: I

The cyclic method of treating waste lead products, tin scrap and galvanized scrap by first dissolving the lead product in caustic soda, then precipitating the spongy leadby means of tin scrap, thus detinning the scrap and forming stannatc of soda; then treat:

ing that solution with galvanized sg'itap. thus dezincing the scrap and formingc zincate f;

soda, then partially .electrolyzin'rg the zincat of soda thereby obtaining metallic zincand a resulting liquor containing zincate of soda and an excess of caustic soda. which is again employed for treating the lead product.

In testimony whereof, I afiix my signature in presence of two witnesses.

ALEXANDER S. RAMAGE. Witnesses: v

J. H. BRIcKnNs'InI'N, G. H. Poms. 

